Crack appeared in external render

We can't diagnose this here but do a bit of reading on "differential settlement", it's a possible cause for cracking where it runs in a diagonal from the footing to the top-plate or side walls through the weakest point (a window).

I would much prefer asking people who have first hand knowledge about certain things than a computer program that gets a lot of simple questions completely wrong. An example would be gluing cheese on a pizza so the airfryer fan won't blow it off! It's useful in some scenarios but anything like this I would prefer a human with experience about the issue giving me the advise.

Oh I know, but I wouldn't be depending on AI to be accurate with certain things so yes it is a useful guide as to possible issues.